The invention relates to a process for rendering inert reactors which contain flammable substances and which are open at least temporarily.
In chemical manufacturing processes in reactors in which flammable substances are situated, the reactor interior is rendered inert. When the reactor is opened, for example in order to charge solids, the oxygen-containing external air can penetrate into the reactor. In order to avoid this penetration of oxygen or to ward off its consequences, various procedures are employed.
In the simplest case, the moments of risk which arise during opening and charging are ignored and, after the reactor cover has been closed, inert-rendering is carried out again if appropriate. It is more effective to feed inert gas during the period of the opening and charging operations. For this purpose so-called inert gas locks are also sometimes used. The inert gas feed usually causes gas exit from the filler opening which prevents entry of air. Inert-rendering is also carried out in this case after the cover has been closed if appropriate. It is safest to measure the residual content of oxygen in the reactor continuously and thus initiate the addition of inert gas through the existing inert-rendering line.
All these processes have disadvantages. Thus the first-mentioned procedure is of concern for safety reasons. In the other two procedures, considerable amounts of flammable vapors are discharged and form an explosion risk or health risk for the handlers. Moreover, fine-grained bulk material can be swirled up against the fall direction and discharged. This can also be a safety or health risk, or at least the production hall is contaminated in an undesirable manner as a result. Moreover, the discharge of vapors and dusts represents an economic loss. Although measurement of the oxygen with the controlling of the inert gas feed associated therewith is highly effective and does not comprise a safety risk, it is so expensive that many operating companies dispense with the procurement thereof.